Papers by Keyword: High Speed Machining (HSM)

Abstract: The results reported in this paper pertain to the simulation of high speed hard turning when using the finite element method. In recent years high speed hard turning has emerged as a very advantageous machining process for cutting hardened steels. Among the advantages of this modern turning operation are final product quality, reduced machining time, lower cost and environmentally friendly characteristics. For the finite element modelling a commercial programme, namely the Third Wave Systems AdvantEdge, was used. This programme is specially designed for simulating cutting operations, offering to the user many designing and analysis tools. In the present analysis orthogonal cutting models are proposed, taking several processing parameters into account; the models are validated with experimental results from the relevant literature and discussed. Additionally, oblique cutting models of high speed hard turning are constructed and discussed. From the reported results useful conclusions may be drawn and it can be stated that the proposed models can be used for industrial application.

Abstract: Surface finish and dimensional accuracy is one of the most important requirements in machining process. Inconel 718 has been widely used in the aerospace industries. High speed machining (HSM) is capable of producing parts that require little or no grinding/lapping operations within the required machining tolerances. In this study small diameter tools are used to achieve high rpm to facilitate the application of low values of feed and depths of cut to investigate better surface finish in high speed machining of Inconel 718. This paper describes mathematically the effect of cutting parameters on Surface roughness in high speed end milling of Inconel 718. The mathematical model for the surface roughness has been developed in terms of cutting speed, feed rate, and axial depth of cut using design of experiments and the response surface methodology (RSM). Central composite design was employed in developing the surface roughness models in relation to primary cutting parameters. Machining were performed using CNC Vertical Machining Center (VMC) with a HES510 high speed machining attachment in which using a 4mm solid carbide fluted flat end mill tool. Wyko NT1100 optical profiler was used to measure the definite machined surface for obtaining the surface roughness data. The predicted results are in good agreement with the experimental one and hence the model can be efficiently used to predict the surface roughness value with in the specified cutting conditions limit.

Abstract: Surface finish and dimensional accuracy is one of the most important requirements in machining process. Inconel 718 has been widely used in the aerospace industries. High speed machining (HSM) is capable of producing parts that require little or no grinding/lapping operations within the required machining tolerances. In this study small diameter tools are used to achieve high rpm to facilitate the application of low values of feed and depths of cut to investigate better surface finish in high speed machining of Inconel 718. This paper describes mathematically the effect of cutting parameters on Surface roughness in high speed end milling of Inconel 718. The mathematical model for the surface roughness has been developed in terms of cutting speed, feed rate, and axial depth of cut using design of experiments and the response surface methodology (RSM). Central composite design was employed in developing the surface roughness models in relation to primary cutting parameters. Machining were performed using CNC Vertical Machining Center (VMC) with a HES510 high speed machining attachment in which using a 4mm solid carbide fluted flat end mill tool. Wyko NT1100 optical profiler was used to measure the definite machined surface for obtaining the surface roughness data. The predicted results are in good agreement with the experimental one and hence the model can be efficiently used to predict the surface roughness value with in the specified cutting conditions limit.

Abstract: High Speed Machining is applicable for producing parts that require little or no grinding / polishing operations within the required machining tolerances. For achieving required level of quality, selection of cutting tools and parameters in high speed machining is very important. In this study, small diameter flat end milling tool was used to achieve high rpm to facilitate the application of low values of feed and depth of cut to achieve better surface roughness. Machining was performed on a Vertical Machining Centre (VMC) with a high speed milling attachment (HES 510), using cutting speed, depth of cut, and feed as machining variables. Statistical prediction model of average surface roughness was developed using three-level full factorial design of experiments. It was observed that depth of cut is the most dominating factor followed by cutting speed and feed. The developed model was used for optimization by desirability function approach to obtain minimum Ra. Maximum desirability of 95.63% was obtained.

Abstract: High speed machining is one of the advanced manufacturing technologies which have developed quickly in recent years. Tool technology is key factor which will make influence to the efficiency and precision of HSM. The paper has analysis the HSM tool technology in terms of material, shank structure and tool balance. It brings forward that tool material with high property must match with workpiece to get high efficiency and precision in HSM. Three type of shank are introduced and using HSK can get better working performance due to its double-surface positioning and short tapered shank. The paper finally put forward the online balancing test technology which can achieves the actual signal collection of dynamic balance, and make technical analysis as well as processing in high-speed cutting.

Abstract: To study the microstructure of white band is helpful for revealing formation mechanism of serrated chip. This paper investigates the microstructural characteristics of white band_s at primary and second deformation zone within the serrated chips produced during High Speed Machining (HSM) of AISI 1045 hardened steel usingoptical microscope, SEM, TEM, and electron microprobe, X-Ray diffraction. It was found that the white bands within primary and second deformation zone consist of small equiaxed grains which formed due to dynamic recrystallization during adiabatic shear, however, martensitic transformation just only taken place within the white band in second deformation zone. The re-distribution of chemical elements between the composition phases occurred due to the combined effect of adiabatic temperature rise and high speed deformation in formation process of white band. The former is result from adiabatic shear in primary deformation zone during formation of chip, while the latter is caused by the intense shear and friction between tool and chip.

Abstract: This paper describes strong nonlinearity in log V-log L relationship, which is often found in machining of supperalloys, titanium alloys, hardened steels, cast irons, etc. The nonlinearity plays an important and favorable role in extension of life-span cutting distance at higher cutting speeds; that is, in a certain range of cutting speed, life-span cutting distance increases with cutting speed. Results of tool wear in a sliding test and cutting experiments, which showed the evidences of strong nonlinearity, were investigated and the mechanisms causing the nonlinearity were discussed.

Abstract: High-speed machining requires the support of high intelligent CAM software as well as customized machining strategies and properly selected machining parameters. Only by combining the two can the advantage of high-speed machining be made full use of. Compared to ordinary NC cutting, high-speed machining has special requirements for process strategies, CAM system and tool path. A complete tool path includes approaching/retracting tool, moving tool and tool path. Based on the above principles, a mould part is successfully processed using the PowerMILL software at the high-speed machining centre of DMG-DMU40T. The maximum hardness of the mould part is HRC50. There’s a 30 degree corner in the cavity with a transition radius of 3mm. The whole process can be divided into three stages: rough, semi-finish and finish machining and each stage involves the selection of tool path, the selection of tool, the selection of cutting parameters (including spindle speed, feed speed and depth of cut), and the application of PowerMILL specific machining methods (such as Race-line machining, rest roughing, automatic trochoidal machining, 3D offset finishing and etc).

Abstract: Experimental explorations for optimal cutting conditions on high speed drilling processes could be expensive and risky both to machine tools and operators. In this study, high-speed drilling of SUS304 stainless steel with a TiN-coated drill was simulated for optimized drilling conditions. Tool wear mechanism as well as chip formation processes was also explored based on finite element analysis (FEA). It was found with the simulations that higher cutting speed came up with smaller tool wear.

Abstract: Polycrystalline diamond (PCD) tools were used in high speed machining of SiCp/2009Al and TiCp/TC4 composites. The results showed that milling forces decreased with the increasing cutting speed, and that the force value of vol.20%SiCp/2009Al was less than that of the matrix. The machined surface roughness Ra is less than 0.8μm for all the milling experiments until cutting time was 180 minutes. The machined surface included some defects such as scratches, craters, micro cracks and so on. Surface finish can be improved through increasing cutting speed. When milling, gradual flank wear and slight edge chipping took place on the PCD tool flank. But no obvious abrasive wear was observed. However, the PCD tool suffered from significant abrasive wear in the flank when turning. A flow type chip was formed either for milling or turning when vol.20%SiCp/2009Al was used. Some voids and micro cracks were found in the chip. For TiCp/TC4 composite, the chip took the form of interrupted saw-toothed due to the dynamic behavior of micro crack. Although PCD tool was very suitable for high speed machining of SiCp/2009Al, its geometry parameters must be rightly chosen for TiCp/TC composite, or else sever edge chipping would take place in a few minutes.